Why can´t I accept the shipped resources?

The resources can be accepted only on the island which was indicated as the destination point when sending the cargo. If it is stated that you can´t unload the cargo on the island please, visit all your islands in turn and check the Inventory in each location. The cargo goes into your Inventory only if warehouses on the destination island are full, otherwise the resources will go straight to your Warehouse. When visiting the islands pay attention to the writing on the cargo: on one of your islands it will change to "Warehouse is full" and you will need to build more warehouses on the island in question or upgrade the ones you already have. Please, note that when upgraded to its maximum capacity (level 4), a warehouse contains 500 units. If you press one of your warehouses you will see the total capacity of these buildings on your island.